1. Field of the Invention
The present invention generally relates to a mobile communication system, and in particular, to an apparatus and method for providing access rejection information to a Man-Machine Interface (MMI) of a User Equipment (UE), such as a mobile phone, a mobile communication terminal, a Personal Digital Assistant (PDA), a notebook computer, etc., and displaying the information when the UE is turned power-on in a suitable cell and the access of the UE to resources of the cell is not permitted in the cell where an access class restriction is set. A suitable cell, as used herein, represents a cell on which the user equipment can normally camp. The phrase camp on or variations thereof, as used herein, means that while residing in a cell, a user equipment receives a service from the cell after the user equipment connects to the cell and until the user equipment moves to another cell.
2. Description of the Related Art
A UE periodically transmits/receives information to/from a network from a moment when the UE is turned power-on to a moment when the UE is turned power-off. When the UE needs to update information, the UE transmits the updated information to the network. Likewise, when the network needs to update information, the network transmits the updated information to the UE. The UE analyzes the updated information transmitted from the network and performs the following process based on a particular scheme, such as a communication protocol.
In particular, the UE searches a cell where the UE is and, when the cell is a suitable cell, the UE camps thereon. The UE then obtains information unique to the cell and acquires location information based on the unique information. The UE also receives system information blocks that are periodically broadcasted in the cell that the UE camps on, and executes the following process based on the received system information blocks and a particular scheme.
FIG. 1 shows a conventional mobile communication system. A Radio Network Controller (RNC) and a User Equipment (UE) execute communication using Radio Resource Control (RRC) layers 110 and 120, Radio Link Control (RLC) layers 130 and 140, Medium Access Control (MAC) layers 150 and 160, and physical layers L1 170 and 180.
As described below, the UE in FIG. 1 represents a mobile communication terminal. However, the UE may be also be configured as a variety of other devices, such as mobile phone, a PDA, a notebook computer, etc.
The physical layers L1 170 and 180 are communication protocols of first layers and they correspond to electrical and mechanical interfaces for communication media. They transform data including access connection and access disconnection into signals that can be communicated among devices of the mobile communication system. The MAC layers 150 and 160 and the RLC layers 130 and 140 are communication protocols of second layers and they execute logical access, link control and error control. The RRC layers 110 and 120 are communication protocols of third layers. They exchange control messages to establish and control the physical layers L1 170 and 180, the MAC layers 150 and 160, and the RLC layers 130 and 140. A Mobility Management (MM) layer 105 is disposed on top of the RRC layer 120, and the MM layer 105 is connected with the radio network controller (RNC) or a mobile switching center (MSC) to manage a position of the UE in motion. A Man-Machine Interface (MMI) 100 communicates with the MM layer 105 to thereby display the current status of the UE, or the MMI 100 receives input data from a user and delivers the data to a lower layer.
When access class restriction information set up on an access class restriction list is the same as access class restriction information set up in a Subscriber Identity Module (SIM) card of the UE among cell restriction information included in a system information block (SIB), the RRC layer 120 of the UE reports the access class restriction information to the MM layer 105. The SIB is transmitted to the RRC layer, analyzed, and its results are transmitted to the MM layer 105.
Subsequently, when the MM layer 105 determines that the MM layer 105 cannot successfully execute registration, the MM layer 105 reports to the MMI 100 that only a limited service can be provided. Under the limited service, only an emergency call is permitted and normal calls are not permitted. When a great deal of subscribers temporarily crowd and make requests for the service that go over the capacity of a base station, the base station may limit access to the service in the cell of the base station.
However, the MMI 100 of the UE cannot receive a cause for the limited service. Since the MMI 100 does not receive information on the cause, the user cannot know whether there is a problem in the UE or in the resource distribution status of the cell.